So far I’ve been able to put the widget across the top, but on all pages, which is not good enough. The hook given above for the home page only doesn’t work in the Balance theme. It breaks the code and my blog crashes (i.e. all you can see is a blank page and you need to re-upload the original .php files)

Yes, lower case is fine. Sorry it wasn’t indicated – I assumed you already knew to do that. Unless you did other modifications to your theme, I just installed the same theme on my demo – made those changes including the one for front page only and it works fine. It did not break the theme.

Yes, replace the second part of Brian’s ORIGINAL code – with that piece of code and it should work. Not sure why your Navigation is disappearing, etc., on your home page. If this doesn’t work. We can use Join.me and I can help you virtually.